In the rapidly evolving field of intravascular treatment of atherosclerotic disease, it has become apparent that removal of atherosclerotic blockages must be carried out without sustaining injury to the arterial wall. Although laser powered devices have been shown to be effective in alleviating atherosclerotic obstructions, the problem of avoiding damage to the arterial wall has not been overcome with a margin of safety appropriate for routine use of these procedures on human beings.
It has been shown in the prior art that laser heated cautery caps are capable of destroying atherosclerotic occlusions while preventing the potential damage associated with the intravascular use of free laser beams. With regard to laser heated cautery cap procedures within the coronary arteries, it is clear that proper guidance of the cap is essential to avoid thermal damage to the arterial wall. Even so, within the narrow confines of the tortuous coronary arteries, contact between the cautery cap and the arterial wall cannot be avoided entirely. Thus it is essential to direct the thermal energy emanating from the laser heated cautery cap toward the atherosclerotic occlusions while protecting the adjacent arterial wall.
The structures disclosed in the copending parent application of the present patent application display the potential for providing both the proper guidance of the laser heated cautery cap and the ability to direct the thermal energy of the cap to the desired target. The present invention comprises significant improvements in the prior inventions. These improvements are direct toward the ultimate goal of removal of atherosclerotic lesions in narrow arterial passages, such as in the coronary arteries, by means of a percutaneous, non-surgical procedure.